Self-dudding arming system for spun ammunition



June 20, 1967 G. L. HAZELET 3,326,131

MMUNITION SELF-DUDDING ARMING SYSTEM FOR SPUN A Filed Jan. 21, 1965 Detonator IN VENTOR. GERALD L. HAZELET Alforne 8 United States Patent 3,326,131 SELF-DUDDING ARMTNG SYSTEM FGR SPUN AMMUNITION Gerald L. Hazelet, Urbana, Ill., assignor to The Magnavox Company, Fort Wayne, lnd., a corporation of Delaware Filed Jan. 21, 1965, Ser. No. 428,284 7 Claims. (Cl. 102--79) This invention relates generally to means for changing the condition of an explosive projectile from a safe to an armed condition for normal utilization thereof, and means capable of returning the projectile to safe condition in the event explosion thereof under intended condition does not occur. More particularly the invention relates to such means applicable to spin stabilized ammunition.

For practical purposes, it is necessary to provide fuze safety devices on projectiles so that hazards are minimized during normal handling prior to use of the projectiles in weapons. Of course it is necessary that some means be provided so that when the ammunition has been fired or launched toward a target, the ammunition will be armed so that it will explode upon contact with the target or upon reaching a certain proximity thereto. In some instances, however, it is desired that in the event the ammunition is not exploded upon reaching a target or proximity thereto, the ammunition will automatically be returned to a safe condition so that if subsequently encountered by the user thereof, it will not present a hazard.

It is, therefore, a general object of the present invention to provide an arming system which will prevent accidental explosions of ammunition while being handled.

A further object is to provide an arming system useful in ammunition which is spin stabilized so as to cause the ammunition to become armed when the spin thereof during or after launching has reached a predetermined minimum speed.

A further object is to provide an arming system which will return the ammunition to a safe condition in the event the rotational speed thereof has dropped below a certain predetermined value, such as could occur in the event the ammunition struck a target or other object and for some reason or other failed to explode in the usual manner.

Described briefly, in a typical embodiment of the present invention, ammunition in the form of a projectile includes a body which is stabilized by spinning it on its longitudinal axis, and wherein a rotor is employed having a portion of the detonator train or initiator therein. Normally, when the ammunition is not spun, the rotor is in a safe or unarmed position whereby the ammunition cannot be exploded. Centrifugally operated rotor safety lock pins are locked in the rotor and body at such times and remain so until a certain minimum spin speed is impaited to the body whereupon centrifugal force of the lock pins overcomes a normal spring bias thereon and the pins unlock the rotor.

The rotor is dynamically unbalanced when the body is spun so that When the rotor lock pins unlock, the rotor rotates on its axis to an ammunition arming condition enabling explosion of the ammunition upon impact or otherwise. A centrifugally operated arming lock pin is mounted in the rotor and is urged by centrifugal force against a wall of the body and is received in a detent in the body when the rotor has moved to armed condition. The disposition of the arming lock pin is such that the centrifugal force thereon provides very little resistance to the starting of the rotor from safe position to armed posi- ?tion but increased resistance as the rotor moves closer to armed position.

A rotor return spring is provided on the rotor and even though the rotor locking detent serves to lock the rotor in armed position so long as the spin speed remains above a predetermined minimum value, the rotor safety lock pin 7 will disable the arming lock pin if spin speed again falls below predetermined value whereupon the rotor is returned to safe position whereby the ammunition is self dudding if the spin speed drops below a predetermined value.

The full nature of the invention will be understood from consideration of the following description and claims together with the accompanying drawings wherein:

FIG. 1 is a side elevational view of a projectile employing a typical embodiment of the present invention.

FIG. 2 is a cross section taken along the line 2-2 in FIG. 1 and viewed in the direction of the arrows, and illustrating the rotor mounted therein.

FIG. 3 is a section taken along the line 3--3 in FIG. 2 and viewed in the direction of the arrows and illustrating the rotor in the safe position.

FIG. 4 is a section taken at the same place as that of FIG. 3 but illustrating the rotor in the armed position.

Referring now to the drawings in detail, projectile 11 has a front end 12 and rear end 13 and is generally cylindrical with respect to the axis 14 on which it is spun in normal flight. The spin can be imparted during launching from a barrel or otherwise.

Inside the projectile there is mounted a rotor 16, this rotor being mounted to permit rotation or pivoting thereon on the axis 17 normal to the spin axis 14, and the mounting for this purpose can be accomplished in any one of a variety of ways. In the illustrated example, it is accomplished by hearing units 18 and 19 received in a transverse bore 21 in the projectile body 22. As is typical in ammunition, the rotor is normally disposed in a safe position until the ammunition has been launched whereupon the rotor is placed in an arming or armed position.

Although the specific nature of the detonating means in the system of the present invention can be any of a variety, one arrangement is shown schematically for purposes of illustration, and includes an electrical contact 23, an impact switch 24, a detonator 26, an electrical contact 27 and an initiator 28. When the rotor is in the safe position shown in FIG. 3, the circuit cannot be completed because the initiator is out of position for cooperating with the other circuit components. However, when the rotor pivots to the armed position shown in FIG. 4, electrical contact between the initiator and the contacts 23 and 27 is achieved whereupon cooperation of the initiator with the other components in the circuit can be obtained and when the front end of the projectile strikes a target, for example, impact switch 24 closes, the circuit is completed, and detonator 26 is fired.

To hold the rotor in the safe position shown in FIGS. 2 and 3, first and second lock pins 29 and 31, respectively are employed, lock pin 29 extending through an aperture 32 in the body of the projectile and lock pin 31 extending through an aperture 33 therein. Pin 29 is received in a detent hole 34 in the rotor and pin 31 is received in the detent hole 36 in the rotor. Both of these lock pins are biased inwardly toward the spin axis 14 by coil springs such as the coil spring 37 engaging the outer face 38 of the lock pin 29. The spring tension can be adjusted by a screw 39 threadedly received in the body 22. The amount of bias applied by the springs on the lock pin can be adjusted by the use of the screws so that when the body 22 is spun on the axis 14 above a predetermined minimum rotational speed, centrifugal force on the pins 29 and 31 will remove the inner ends thereof from the holes in the rotor to unlock the rotor.

The rotor is constructed so that the center of gravity 41 thereof is offset with respect to a plane 42 which contains the pivotal axis 17 of the rotor and which is perpendicular to the spin axis 14. Therefore, the rotor is dynamically unbalanced when the projectile is spun, and the center of gravity tends to move to the point 43 which lies in the plane 42. The arcuate angle between the center of gravity 41 and the plane 42 should be equal to or slightly greater than the arcnate angle between the pin 51 and the plane 42. In other words, the center of gravity 41 is located relative to the plane 42 so that when the center of gravity 41 reaches the point 43, the pin 51 will have reached the position of the lock pin 31. It is actually advantageous to have the angle between the center of gravity 41 and the plane 42 greater than the angle between the pin 51 and the plane 42 so that there is always a driving torque available no matter how closely the pin 51 approaches the lock pin 31. Also, a couple can be utilized whereby the center of gravity is symmetrically positioned on opposite sides of the axis 41. so that the system is statically balanced, but dynamically unbalanced. Environmental vibrations will consequently not cause a torque to be generated by the rotor 16, but spin forces will still operate the system. A coil spring in the form of a flat spiral 44 has one end 46 connected to the body of the projectile and the other end 47 connected to the rotor. Normally these ends are received in slots 48 and 49 in the projectile body and rotor, respectively. The spring 44 opposes rotation of the rotor in the direction of the arrow 50 and accordingly the spring is wound when the unbalance of the rotor causes the rotor to pivot in the direction of the arrow 50.

It is desirable to lock the rotor in the armed position shown in FIG. 4. For this purpose, a rotor arming lock pin 51 is employed. This pin is received in a cavity 52 in the rotor, which cavity is closed by a plug 53 having an aperture therein receiving the outer end of the pin. When the rotor has rotated to the armed position, the aperture 54 in the plug is in registry with the aperture 33 in the projectile body and the centrifugal force on the rotor arming lock pin in effective to cause the outer end of the pin to enter the aperture 33 in the body. As it does so, the safety lock pin 31 is moved further out against the bias of the spring 56. Pin 51 thereby locks the rotor in the armed condition.

In the event that the spin speed of the projectile decreases below a certain predetermined value, the bias of the spring 56 against pin 31 will push the lock pin 51 back into the cavity 52 until it bottoms against the bottom 57 of the cavity. When pin 51 bottoms, the outer end is flush with the outer cylindrical surface 70 of the rotor so that pin 31 does not enter aperture 54 in the plug. Therefore, the rotor is again unlocked. The torque generated in the spring 44 will thereupon return the rotor to the safe position as spin speed decreases until the rotor safety lock pins again enter the holes 34 and 36, whereupon the rotor is again locked in the safe or unarmed position.

A feature of the present invention is the fact that the outer end 58 of the rotor arming lock pin engages the wall of the bore 21 in the projectile body. This feature together with the fact that the direction of possible relative movement between the lock pin 51 and the body is perpendicular to the pivotal axis 17 thereof, and the further fact that this direction approaches a condition parallel to the plane 42 as the center of gravity approaches the plane, causes the centrifugal force applied by the outer end of the pin to the wall of the bore 21 to increase as the rotor comes increasingly close to the armed position. Therefore, although the centrifugal force of the lock pin against the wall of the bore 21 is comparatively low when rotation of the rotor from the safe position begins, the force increases considerably as the rotor approaches the armed position. This assures that the projectile will not become armed too quickly when spin is initiated and thereby provides adequate time for the projectile to reach a safe distance from the launching site before the projectile becomes armed.

From the foreging description, it is believed apparent that the operation of the present invention provides a fuze for spin stabilized ammunition, with means to self-dud itself upon removal of its normal flight environment.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

1. A self-dudding arming system for spun ammunition or the like comprising:

a projectile including a body having a spin axis extending therethrough and on which said projectile is spun during flight;

a rotor disposed in said body and rotatable therein on a rotor axis normal to said spin axis, said rotor being rotatable on said rotor axis from an unarmed position to an armed position, the center of gravity of said rotor being offset from said rotor axis and disposed nearer said spin axis when said rotor is in said unarmed position than it is when said rotor is in said armed position, said rotor having a first safety pin recess therein and a second safety pin recess therein, said recesses having axes normal to said spin axis;

first and second safety pin apertures disposed in said body and registering with said first and second safety pin recesses, respectively, when said rotor is in said unarmed position;

first and second rotor safety lock pins disposed in first and second cavities, respectively, in said body, said first pin projecting through said first safety pin aperture into said first safety pin recess in said rotor when said rotor is in said unarmed position, and said second safety pin projecting through said second aperture into said second recess when said rotor is in said unarmed position;

a first bias spring normally urging said first safety pin into said first recess, and a second bias spring normally urging said second safety pin into said second recess whereby said rotor is normally locked in said unarmed position and prevented from rotation in said body, said first and second safety pins being responsive to spinning of said body on said spin axis above a predetermined minimum spin speed to move outwardly against the bias of said bias springs and exit from said recesses and permit said rotor to rotate in said body, the rotor thereupon beginning to rotate in said body as the center of gravity of said rotor seeks a position more remote from said spin axis than the position thereof when said rotor is in said unarmed position;

a torsion spring having one portion connected to said body and another portion connected to said rotor and disposed to oppose rotation of said rotor, from said unarmed position to said armed position, said spring being wound by said rotor as said rotor rotates from said unarmed position toward said armed position;

a first electrical contact, an impact switch, a detonator, and a second electrical contact, disposed in series circuit relationship in said body;

an electrical initiator disposed in said rotor and operable in a series circuit with contact only when said rotor is in said armed position;

a rotor arming lock pin disposed in a cavity in said rotor, said pin having a portion engaging a wall of said body and retained in a predetermined position in said cavity by said wall when said rotor is in said unarmed position, said arming lock pin and the cavity receiving it being disposed with respect to said spin axis such that spinning of said body on said spin axis urges said arming lock pin against said wall of said body, said rotor arming lock pin being receivable in said second aperture in said body when said rotor moves to said armed position to thereupon lock said rotor in said armed position, the orientation of said cavity and said rotor arming lock pin being such that the direction of motion of said rotor arming lock pin relative to said rotor is along a line perpendicular to said rotor axis and passing through said center of gravity whereby the force of said rotor lock pin against said wall of said body increases as said rotor moves from said unarmed position to said armed position thereby accommodating a low rotor starting torque as said rotor begins movement from said unarmed position toward said armed position and increasing resistance to rotation of said rotor to said armed position as said rotor moves from said unarmed position toward said armed position, said increasing resistance being caused by the increased force of said rotor arming lock pin sliding along said wall as said rotor turns to said armed position, said rotor arming lock pin being removed from said aperture and returned to said predetermined position in said rotor cavity by said second safety lock pin and the biasing spring thereof when the spin speed of said body decreases below a predetermined value whereupon said torsion spring returns said rotor from said armed position to said unarmed position for again receiving said first and second safety lock pins in said first and second recesses, respectively, to lock said rotor in said unarmed position for self-dudding when spin speed decreases below said predetermined value.

2. A self-dudding arming system for spun ammunition or the like comprising:

a projectile including a body having a spin axis extending therethrough and on which said projectile is spun during flight;

a rotor disposed in said body and rotatable therein on a rotor axis from an unarmed position to an armed position, the center of gravity of said rotor being offset from said rotor axis and disposed nearer said spin axis when said rotor is in said unarmed position than it is when said rotor is in said armed position, said rotor having a first safety pin recess therein with an axis normal to said spin axis;

a first safety pin aperture disposed in said body and registering with said first safety pin recess when said rotor is in said unarmed position;

a first safety lock pin disposed in a first cavity in said body, said first pin projecting through said first safety pin aperture into said first safety pin recess in said 0 rotor when said rotor is in said unarmed position;

a first bias spring normally urging said first safety pin into said first recess whereby said rotor is normally locked in said unarmed position and prevented from rotation in said body, said first safety pin being responsive to spinning of said body on said spin axis above a certain predetermined minimum spin speed to move outwardly against the bias of said biasspring and exit from said first recess permitting said rotor to rotate in said body, the rotor thereupon beginning to rotate in said body as the center of gravity of said rotor seeks a position more remote from said spin axis than the position thereof when said rotor is in said unarmed position;

a rotor return spring having one portion connected to said body and another portion connected to said rotor and disposed to oppose rotation of said rotor from said unarmed position to said armed position, said return spring being wound by said rotor as said rotor rotates from said unarmed position toward said armed position;

detonator means disposed in said rotor and said body and coope-rable only when said rotor is in said armed position;

a rotor arming lock pin disposed in a second cavity in said rotor, said arming pin having a portion engaging a wall of said body and retained in a predetermined position in said second cavity by said wall when said rotor is in said unarmed position, said arming lock pin and said second cavity receiving it being disposed with respect to said spin axis such that spinning of said body on said spin axis urges said arming lock pin against said wall of said body, said rotor arming lock pin being receivable in said first safety pin aperture in said body when said rotor moves to said armed position to thereupon lock said rotor in said armed position, the orientation of said second cavity and said rotor arming lock pin being such that the direction of motion of said rotor arming lock pin relative to said rotor is along a line such that the force of said rotor lock pin against said wall of said body increases as said rotor moves from said unarmed position to said armed position, thereby accommodating a low rotor starting torque as said rotor begins movement from said unarmed position toward said armed position and increasing resistance to rotation of said rotor to said armed position as said rotor moves from said unarmed position toward said armed position, said increased resistance being caused by the increased force of said rotor arming lock pin sliding along said wall as said rotor turns to said armed position, said rotor arming lock pin being removed from said first safety pin aperture by said first safety lock pin and the biasing spring thereof when the spin speed of said body decreases below a predetermined value whereupon said rotor return spring returns said rotor from said armed position to said unarmed position for again receiving said first safety lock pin in said first recess to thereupon lock said rotor in said unarmed position for self-dudding when spin speed decreases below said predetermined value.

3. A self-dudding arming system for spun ammunition or the like comprising:

a projectile including a body having a spin axis extending therethrough and on which said projectile is spun during flight;

a rotor disposed in said body and rotatable therein on a rotor axis from an unarmed position to an armed position, the center of gravity of said rotor being offset from said rotor axis and disposed nearer said spin axis when said rotor is in said unarmed position than it is when said rotor is in said armed position, said rotor having a first safety pin recess therein;

a first rotor safety lock pin disposed in a cavity in said body, said first pin projecting into said first safety pin recess in said rotor when said rotor is in said unarmed position;

a first bias spring normally ur ing said first safety pin into said first recess whereby said rotor is normally locked in said unarmed position and prevented from rotation in said body, said first safety pin being responsive to the spinning of said body on said spin axis above a certain predetermined minimum spin speed to move outwardly against the bias of said bias spring and exit from said recess permitting said rotor to rotate in said body, the rotor thereupon beginning to rotate in said body as the center of gravity of said motor seeks a position more remote from said spin axis than the position thereof when said rotor is in said unarmed position;

a rotor return spring having one portion connected to said body and another portion connected to said rotor and disposed to oppose rotation of said rotor from said unarmed position to said armed position, said rotor return spring being wound by said rotor as said rotor rotates from said unarmed position toward said armed position;

detonator means disposed in said rotor and said body and cooperable only when said rotor is in said armed position;

a rotor arming lock pin disposed in a second cavity in said rotor, said pin having a portion engaging a wall of said body and retained in a predetermined position in said second cavity by said wall when said rotor is in said unarmed position, said arming lock pin and said second cavity receiving it being disposed with respect to said spin axis such that spinning of said body on said-spin axis urges said arming lock pin against said wall of said body, said rotor arming lock pin being receivable in a detent in said body when said rotor moves to said armed position to thereupon lock said rotor in said armed position, the

orientation of said second cavity and said rotor arming lock pin being such. that the direction of motion of said rotor arming lock pin relative to said rotor is along a line such that the force of said rotor arming lock pin against said wall of said body increases as said rotor moves from said unarmed position to said armed position, thereby accommodating a low rotor starting torque as said rotor begins movement from said unarmed position toward said armed position and increasing resistance to rotation of said rotor to said armed position as said rotor moves from said unarmed position toward said armed position, said increased resistance being caused by the increased force of said sliding rotor arming lock pin sliding along said wall as said rotor turns to said armed position;

means removing said rotor arming lock pin from said detent when the spin speed of said body decreases below a predetermined value whereupon said rotor return spring returns said rotor from said armed position to said unarmed position for again receiving said safety lock pin in said first recess to thereuponlock said rotor in said unarmed position for self-dudding when spin speed decreases below said predetermined value.

4. A self-dudding arming system for spun ammunition or the like comprising:

a projectile including a body having a spin axis extending therethrough and on which said projectile is spun during flight;

a rot-or disposed in said body and rotatable therein on a rotor axis from an unarmed position to an armed position, the center of gravity of said rotor being offset from said rotor axis and disposed nearer said spin axis when said rotor is in said unarmed position than it is when said rotor is in said armed position, said rotor having first detent means therein;

a first rotor safety detent member disposed in said body and normally biased into engagement with said first detent means when said rotor is in said unarmed position to lock said rotor in said unarmed position and thereby prevent it from rotation in said body, said first detent member being responsive to spinning of said body on said spin axis above a certain predetermined minimum spin speed to disengage from said first detent means and permit said rotor to rotate in said body, the rotor thereupon beginning to rotate in said body as the center of gravity of said rotor seeks a position more remote from said spin axis than the position thereof when said rotor is in said unarmed position;

a rotor return spring having one portion connected to said body and another portion connected to said rotor and disposed to oppose rotation of said rotor from said unarmed position to said armed position, said spring being wound by said rotor as said rotor rotates from said unarmed position toward said armed position;

detonat-or means having a portion disposed in said rotor and a portion disposed in said body, said portions being cooperable only when said rotor is in said armed position;

a rotor arming lock detent member disposed in said rotor, said arming detent member having a portion engaging a wall of said body and retained in said rotor by said wall when said rotor is in said unarmed position, said arming detent member being disposed with respect to said spin axis such that the spinning of said body on said spin axis urges said rotor arming detent member against said wall of said body, said rotor arming detent member being engageable with second detent means located in said body when said rotor moves to said armed position to thereupon lock said rotor insaid armed position, the orientation of said rotor arming detent member in said rotor and the direction of possible relative movement between saidarming detent member and said rotor being such that the force of said arming detent member against said wall of said body increases as said rotor rotates from said unarmed position toward said armed position, thereby providing a low resistance to said rotor star-ting movement from said unarmed position. to ward said armed position and increasing resistance to rotation of said rotor to said armed position as said rotor moves from said unarmed. position toward said armed position;

- dudding means in said body responsive to decrease of spin speed of said body below a predetermined value to move said rotor arming detent member out of engagement with said second detent means thereby enabling said rotor return spring to return said rotor from said armed position to said unarmed position for again engaging said rotor safety detent member with said first detent means to thereupon lock said rotor in said unarmed position.

5. A self-returning enabling system for spun devices comprising:

a body having a spin axis extending therethrough and on which said body is spun;

a rotor disposed in said body and rotatable therein on a rotor axis from a first position to a second position, the center of gravity of said rotor being offset from said rotor axis and disposed nearer said spin axis when said rotor is in said first position than it is when said rotor is in said second position, said rotor having first detent means therein;

a first rotor detent member disposed in said body and normally biased into engagement with said first detent means when said rotor is in said first position to lock said rotor in said first position and thereby prevent it from rotation in said body, said first detent member being responsive to spinning of said body on said spin axis above a certain predetermined minimum spin speed to disengage from said first detent means and permit said rotor to rotate in said body, the rotor thereupon beginning to rotate in said body as the center of gravity of said rotor seeks a position more remote from said spin axis than the position thereof when said rotor is in said first position;

a rotor return spring having one portion connected to said body and another portion connected to said rotor and disposed to oppose rotation of said rotor from said first position to said second position, said spring being wound by said rotor as said rotor rotates from said first position toward said second position;

a second rotor detent member disposed in said rotor, said second member having a portion engaging a Wall of said body and retained in said rotor by said wall when said rotor is in said first position,

9 said second detent member being disposed with respect to said spin axis such that the spinning of said body on said spin axis urges said second detent member against said wall of said body, said second 10 gageable by said second lock member and movable thereby out of engagement with said second detent in said body when said rotor is in said second position and the spin speed of said body falls below said detent member being engageable with second detent predetermined value, to enable return of said rotor means located in said body when said rotor moves from said second position to said first position. to said second position to thereupon lock said rotor 7. A self-returning enabling system for spun devices in said second position, the orientation of said seccomprising: ond detent member in said rotor and the direction a body having a spin axis on which said body is spun; of possible relative movement between said second a member disposed in said body and movable therein detent member and said rotor being such that the from a first position to a second position, the center force of said second detent member against said of gravity of said member being disposed nearer said wall of said body increases as said rotor rotates spin axis when said member is in said first position from said first position toward said second position, than it is when said member is in said second posithereby providing a low resistance to said rotor tion, said member having first detent means therein; starting movement from said first position toward second detent means disposed in said body and norsaid second position and increasing resistance to mally engaging said first detent means when said rotation of said rotor to said second position as member is in said first position to lock said member said rotor moves from said first position toward in said first position, said second detent means being said second position; responsive to spinning of said body on said spin axis means in said body responsive to decrease of spin above a certain predetermined minimum spin speed speed of said body below a predetermined value to to disengage from said first detent means and permit move said second rotor detent member out of en- Said member to move in said body, said member gagement with said second detent means thereby thereupon beginning to move in said body as the cenenabling said rotor return spring to return said ter of gravity thereof seeks a position more remote rotor from said second position to said first posifrom said spin axis than the position thereof when tion for again engaging said first rotor detent memsaid member is in said first position; her with said first detent means to thereupon lock resilient return means engaging said member and i id rotor i id fi iti posed to oppose movement of said member from said 6 I an armi g System f spun iti or the first position to said second position, the bias of said like, the combination comprising: resilient means being increased as said member moves a body having a spin axis and spun on said axis during from said first position toward said second position; fli ht; third detent means disposed in said member, said third a rotor having first detent means, said rotor being pivotdetent means being Oriented t0 r sp nd t spinning ll mounted on a i l i i id body d dyof said body on said spin axis and increase resistance namically unbalanced when said body is spun on said to movement of said member as i mem er m ves spin axis, said rotor therefore tending to rotate from further from said first Position toward said second a first position to a second position with respect to POsltiOIl; said body due to said unbalance as said body is spun fourth detent means disposed in said y, aid third on said spin axis; detent means being engageable with said fourth dea rotor lock member disposed in said rotor and entent means when said member has moved to said secgaged with a second detent in said body When said ond position to lock said member in said second rotor pivots to said second position to thereupon lock position; said rotor in said second position, the attitude of said d means in said body responsive to decrease of spin lock member in said rotor being such that centrifugal peed of aid body below a predetermined value to force salfi lock msmbes as said P y is spun move said third detent means out of engagement with 1 5pm axls urges Pomon of Sald F mfimber said fourth detent means and thereby enable return agfimst a Wall of Sa 1d body and the Onentatlon of of said member from said second position to said sald lock member being such that the amount of force first position for again engaging said first detent exemfd on sald.wan by sald.1ock i y Increases means with said second detent means to thereupon as said rotor pivots from said first position toward 1 k b fi t said second position, whereby the torque generated 0c Sal mem er m S 1 rs p051 by said lock member engaging said wall and 0 osin pivoting of said rotor increases as said rotor pivoti References C'ted toward said second position, a second lock member NITED STATES PATENTS mounted in said body and biased toward said first 1,561,687 11/1925 Brayton detent means In said rotor, sald second loclcmem- 2,921,526 1/1960 Hamilton ber belng engaged Wlth sald first detent means in said 3,013,496 12/1961 Wenig 102 82 X rotor when sa1d rotor 1s 1n said first position and when 3,211,099 10/1965 Popovitch 102 79 the spin speed of said body is below a predetermined value, said second look member being movable out of engagement with said first detent means in said rotor when the spin speed of said body exceeds a predetermined value, said rotor lock member being en- SAMUEL FEINBERG, Primary Examiner. BENJAMIN A. BORCHELT, Examiner. G. H. GLANZMAN, Assistant Examiner. 

7. A SELF-RETURNING ENABLING SYSTEM FOR SPUN DEVICES COMPRISING: A BODY HAVING A SPIN AXIS ON WHICH SAID BODY IS SPUN; A MEMBER DISPOSED IN SAID BODY AND MOVABLE THEREIN FROM A FIRST PORTION TO A SECOND POSITION, THE CENTER OF GRAVITY OF SAID MEMBER BEING DISPOSED NEARER SAID SPIN AXIS WHEN SAID MEMBER IS IN SAID FIRST POSITION THAN IT IS WHEN SAID MEMBER IS IN SAID SECOND POSITION, SAID MEMBER HAVING FIRST DETENT MEANS THEREIN; SECOND DETENT MEANS DISPOSED IN SAID BODY AND NORMALLY ENGAGING SAID FIRST DETENT MEANS WHEN SAID MEMBER IS IN SAID FIRST POSITION TO LOCK SAID MEMBER IN SAID FIRST POSITION, SAID SECOND DETENT MEANS BEING RESPONSIVE TO SPINNING OF SAID BODY ON SAID SPIN AXIS ABOVE A CERTAIN PREDETERMINED MINIMUM SPIN SPEED TO DISENGAGE FROM SAID FIRST DETENT MEANS AND PERMIT SAID MEMBER TO MOVE IN SAID BODY, SAID MEMBER THEREUPON BEGINNING TO MOVE IN SAID BODY AS THE CENTER OF GRAVITY THEREOF SEEKS A POSITION MORE REMOTE FROM SAID SPIN AXIS THAN THE POSITION THEREOF WHEN SAID MEMBER IS IN SAID FIRST POSITION; RESILIENT RETURN MEANS ENGAGING SAID MEMBER AND DISPOSED TO OPPOSE MOVEMENT OF SAID MEMBER FROM SAID FIRST POSITION TO SAID SECOND POSITION, THE BIAS OF SAID RESILIENT MEANS BEING INCREASED AS SAID MEMBER MOVES FROM SAID FIRST POSITION TOWARD SAID SECOND POSITION; THIRD DETENT MEANS DISPOSED IN SAID MEMBER, SAID THIRD DETENT MEANS BEING ORIENTED TO RESPOND TO SPINNING OF SAID BODY ON SAID SPIN AXIS AND INCREASE RESISTANCE TO MOVEMENT OF SAID MEMBER AS SAID MEMBER MOVES FURTHER FROM SAID FIRST POSITION TOWARD SAID SECOND POSITION; FOURTH DETENT MEANS DISPOSED IN SAID BODY, SAID THIRD DETENT MEANS BEING ENGAGEABLE WITH SAID FOURTH DETENT MEANS WHEN SAID MEMBER HAS MOVED TO SAID SECOND POSITION TO LOCK SAID MEMBER IN SAID SECOND POSITION; AND MEANS IN SAID BODY RESPONSIVE TO DECREASE OF SPIN SPEED OF SAID BODY BELOW A PREDETERMINED VALUE TO MOVE SAID THIRD DETENT MEANS OUT OF ENGAGEMENT WITH SAID FOURTH DETENT MEANS AND THEREBY ENABLE RETURN OF SAID MEMBER FROM SAID SECOND POSITION TO SAID FIRST POSITION FOR AGAIN ENGAGING SAID FIRST DETENT MEANS WITH SAID SECOND DETENT MEANS TO THEREUPON LOCK SAID MEMBER IN SAD FIRST POSITION. 